Modbus Poll Blog
Articles, guides, and tutorials for Modbus Poll.
Modbus Poll vs Modscan vs Modbus Slave: Which Master Tool to Use
Modbus Poll, Modscan, and Modbus Slave compared. Platform support, RTU vs TCP, master and simulator modes, pricing, and which Modbus master tool fits your workflow in 2026.
Read articleModbus TCP vs PROFINET: Choosing the Right Industrial Ethernet
Modbus TCP vs PROFINET compared. Real-time determinism, device discovery, configuration effort, vendor ecosystem, and when to use each industrial Ethernet protocol.
Read articleHow to Read Modbus Holding Registers (FC03): A Practical Walkthrough
How to read Modbus holding registers with function code 03. Slave ID, start address, quantity, the FC03 frame, 16-bit byte order, and 32-bit scaling explained.
Read articleModbus 32-Bit Data Types: Register Pairs, Byte Order, Scaling
How Modbus handles 32-bit integers: two registers per value, word order (high word first vs low word first), signed vs unsigned, register pairs, and scaling examples for energy meters and drives.
Read articleModbus Addressing: PLC Address vs Protocol Address (Off-By-One)
Why Modbus holding register 40001 is protocol address 0. The PLC address vs protocol address off-by-one confusion, the four address ranges, and how to convert between them.
Read articleModbus TCP Security Risks: Why It Is Not Safe and How to Protect It
Modbus TCP has no authentication, encryption, or integrity: anyone on the network can read and write every register. Segment, firewall, and tunnel it; never expose TCP/502.
Read articleModbus RTU Troubleshooting Guide: CRC Errors, Timeouts, and Wiring
Fix Modbus RTU communication errors. Step-by-step troubleshooting for CRC errors, timeouts, and wiring problems. How to read Modbus RTU frames and diagnose RS485 bus issues.
Read articleBest Modbus Simulator in 2026: Free and Paid Tools Compared
Need to test Modbus devices without hardware? Compare five Modbus simulators: Modbus Poll, Modbus Slave, diagslave, PyModSlave, and ModRSsim2. Covers macOS, Windows, Linux.
Read articleWhat Is Modbus? The Protocol That Runs Industrial Automation
Modbus explained for engineers: how it works, why it's still dominant after 50 years, and the difference between Modbus RTU, TCP, and ASCII.
Read articleModbus Register Types: Coils, Inputs and Holding Registers
The four Modbus data types and their function codes. How to read coils (FC01), write registers (FC06/FC16), and avoid common addressing mistakes.
Read articleModbus RTU vs TCP, and the RTU to TCP Gateway
How Modbus RTU and TCP differ in speed, wiring and distance, and how an RTU to TCP gateway routes requests by unit ID, where its latency really comes from, and hardware vs software gateways.
Read articleBest Modbus Simulator for macOS (2026): PM5560, SMA Inverter, and More
Modbus simulator with real device templates. Simulate Schneider PM5560 power meter, SMA solar inverter, ABB analyzer on macOS. No Parallels, no Windows.
Read articleSchneider PM5560 Modbus Register Map and Simulator
Complete PM5560 Modbus register map with addresses for voltage, current, power, power factor, frequency, and energy. Includes a PM5560 simulator for macOS.
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